While ranking factors are a controversial topic in the SEO world, they’re also something SEOs love to speculate about and test in order to learn more about Google.

Last year, Brian Dean of Backlinko created a list of 200 Google ranking factors that took the SEO world by storm. One half hated it because they thought it was presumptuous to assume the factors, and the other half loved it because it was a great piece of content that sparked interesting discussions.

Now, there are plenty of ranking factors we know to be true. There are also some that have been tested to death, but never officially confirmed. And finally, some are simply theory based on correlation.

Either way, it’s fun to dig into the world of ranking factors.

So with that in mind, here are five of the lesser-known factors that could be affecting your website’s rankings:

Domain History

Back in 2006, Matt Cutts made comments on public vs. private WhoIs domain information. He alluded that someone who uses private information to hide their identity might be up to something they don’t want the public to know about.